Consequences of using kill -9 for node processes?

Question

When reading mongodb's documentation one of the thing that stood out was:

WARNING:

Never use kill -9 (i.e. SIGKILL) to terminate a mongod instance.

I've been running into issues while using foreman start to start my node server. Foreman will start up multiple node processes with the same PID.

However the problem is that when I stop my node process, node won't actually stop running and continues to use the port it was listening on.

To work around this I've been using sudo kill -9 <PID> for the node process I want to terminate. Are there any negative consequences to doing this?

Also, why does Mongo warn against using kill -9 to terminate a mongod instance?

Answer 1

It doesn't give the process a chance to cleanly:

1) shut down socket connections

2) clean up temp files

3) inform its children that it is going away

4) reset its terminal characteristics

These are the bad consequences of what can happen when you use kill -9. You should only use kill -9 as a last resort if all else has failed.

And to the second question, because kill -9 will kill the process even if it is in the middle of doing something while kill will shutdown the process after a clean exit.